Just my two cents but it seems they're really just trying to balance out total time taken for each type of endgame weapon.

Mythics 450-600 mil gil worth of alexandrite + insane amounts of other stuff > ws trials > 3 pandemonium drops
so the biggest crash and time sync for a mythic is the first step 50 weeks of einerjar farming 450-600mil worth of alexandrite

Empyreans a week of trial nms + 50 nm items + 50 nm items > 75 items + 1500 hmps > 60 rift items
The heavy metal plates are 150mil of items the 60 rift items make up for the difference between mythics and empyreans and all of these items are buyable unlike ichor from einerbibble

Relics 150 mil-ish worth of coins > ws trials > 5 arch dl items

I don't know how balanced it is just yet but it would seem there will be alot more finished relics before empyreans or mythics.